What if you connected the outlet to a flow meter (like what you would use to measure the flow when setting/testing pressure-reducing valves)? If you got good numbers for flow and pressure at the riser, wouldn’t this be just about the most accurate way to do it? Since you have actual data at the riser, how is that not better than theoretical data (calcs) to get from the water supply (hydrant) to the base of riser?
Now, if your system demand is significantly more than what you can flow out of the main drain, then I would have some concern about the accuracy farther out on the curve. But otherwise, I don’t understand why this wouldn’t be acceptable. -Kyle M From: Sprinklerforum [mailto:[email protected]] On Behalf Of Salvatore Izzo Sent: Monday, March 11, 2019 9:03 AM To: [email protected] Subject: [EXTERNAL] Re: Hydrant Flow vs Drain test A main drain test out of a 2 inch main drain valve is not capable of measuring the full capacity of the water supply on a municipal water system, nor would it yield accurate results. For example a significant pressure drop on a 2 inch main drain test would indicate a possible closed valve on the lead in piping from the supply main, thus not truly measuring the main capacity. So agreeing with Mr. Bilbo, would never rely on a 2 inch main drain test for designing a fire sprinkler system. On Mon, Mar 11, 2019 at 11:56 AM Skyler Bilbo <[email protected]<mailto:[email protected]>> wrote: I may do this sometimes, just to get an idea of the water supply, early on in a bid, but I would never rely on this for the design of a fire sprinkler system. There are a lot of reasons for this. If you do a quick internet search for "Water Measurement Using Two Inch Drain Tests", you will find a pretty awesome educational resource for this. Make sure you read the whole thing. Again, do not rely on a drain test. -Skyler _______________________________________________ Sprinklerforum mailing list [email protected]<mailto:[email protected]> http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org<https://urldefense.proofpoint.com/v2/url?u=http-3A__lists.firesprinkler.org_listinfo.cgi_sprinklerforum-2Dfiresprinkler.org&d=DwMFaQ&c=wn3mZQLIuInh2ClcJ0_DIA&r=Z_2A85VL7AQzoqudh6uOyS3bn8etxB7nLN8OBJwQd9A&m=xnimhpdXFBaFmEJxZU282pSRPWA5ElSaxlLLyLjgh98&s=ccTTEWN6W9nK2sMDqlYn6lKqYQLGXEsuLQCJlIM8INE&e=>
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